Wave-motion reducing structure

ABSTRACT

A wave-motion reducing structure comprises wave-motion reducing means ( 30 ) suitable for being laid on a coastal bed and restraining means ( 20, 22 ) suitable for restraining the wave-motion reducing means on the coastal bed. The wave-motion reducing means ( 30 ) are arranged so as to be inclined, in use, against the direction of the sea current which strikes them. A wave-motion reducing system comprises a plurality of wave-motion reducing structures arranged in a row lengthwise and in a manner such that the wave-motion reducing means ( 30 ) adopt a substantially parallel configuration and oppose the motion of the current.

The present invention relates to the field of wave-motion reducingstructures and, more particularly, to a wave-motion reducing structureand to a wave-motion reducing system comprising the structure.

As is known, erosion in progress on coastlines often requires theimplementation of measures to prevent such processes. Known structuresthat are used for resisting erosion, such as breakwaters or groynes, mayon the one hand bring advantages in the beach front region but, on theother hand, give rise to erosion processes at the bases of thestructures, in the lateral areas, and in the spaces between thestructures. Moreover, known structures cause so-called “rip” currents or“undertows”, particularly in the direction away from the land towardsthe open sea, which are damaging to coasts. Another disadvantage ofthese structures is therefore the need for constant maintenance andrefilling works which are expensive and impose a burden on the funds ofbodies responsible for coastal maintenance.

The object of the present invention is to solve the problems of theprior art by providing a wave-motion reducing structure and system theuse of which achieves not only a substantial reduction in wave motionbut, in addition, a more homogeneous redistribution of the energy of thesea current in the surrounding areas, thus safeguarding the integrity ofcoasts and extending the useful life of coastal refilling orreconstruction operations.

A further object of the present invention is to provide a system whichaffords maximum safety with regard to bathing conditions on the adjacentbeach when in use on a coast. Another object is to ensure effectivedamping of the wave motion in the long term without requiringexceptional maintenance to the system or to the structures of which thesystem is composed.

A further object of the present invention is to reduce the managementand maintenance costs of a wave-motion reducing system in comparisonwith known solutions.

To achieve the objects indicated above, the subject of the invention isa wave-motion reducing structure and a wave-motion reducing system asdescribed in the appended claims.

One of the main advantages of the present invention is that of reducingthe energy of the wave motion without damaging the original structure ofthe sea bed, in particular, by damping transverse and lateral currentsand preventing the raising of the waterline or “set up” line level, thuspreventing erosion and modification of the shape of the coastline.

The structure and the system according to the invention advantageouslyachieve an optimal reduction in the energy of the wave motion whencombined with anti-erosion filters, so that coast refilling operationscan be carried out to re-establish the eroded beach in an enduringmanner.

Further characteristics and advantages will become clear from thefollowing detailed description relating to the appended drawings whichare provided purely by way of non-limiting example and in which:

FIGS. 1 and 2 are a side view and a plan view, respectively, of oneembodiment of a wave-motion reducing structure according to the presentinvention,

FIG. 3 is a front view of a panel of the structure shown in FIGS. 1 and2,

FIG. 4 is a side view of a wave-motion reducing system according to thepresent invention, and

FIG. 5 is a top elevational view of a particular configuration of thewave-motion reducing system according to the present invention,comprising ballasted filter mats.

With reference now to the drawings, a wave-motion reducing structure,generally indicated 10, comprises wave-motion reducing means, forexample, but in non-limiting manner, at least one panel 30, andrestraining means which are particularly suitable for restraining thewave-motion reducing means on a coastal bed in use.

According to a preferred embodiment of the present invention shown inFIGS. 1 to 3, the restraining means comprise a base suitable for beinglaid on or fixed to a coastal bed. The base comprises a pair oflongitudinal elements 20, for example, of elongate parallelepipedalshape, arranged parallel to one another and interconnected by transverseelements 26 so as to form a structure of overall rectangular shape inplan. Each longitudinal element 20 comprises, on its upper surface, twoparallel projecting walls 22 which are inclined to the vertical,defining a seat 21. The seat 21 is particularly suitable for housing thepanel 30 in use so as to restrain it on the base.

The panel 30 which, for example, is substantially parallelepipedal inshape, comprises a lower portion, for example a foot 31, which can befitted in the seat 21 in complementary manner, and an upper portion 37which bears on the insides of the seats 21 in use, by means ofrespective lower shoulders 38, thus achieving a firm restraint. Thepanel 30 is preferably but not necessarily arranged so as to be inclinedagainst the direction of the sea current which strikes it, preferably atan angle of between 30° and 90° to the horizontal, more preferably 45°or 60°.

According to a particularly advantageous embodiment of the presentinvention, the longitudinal elements 20 and the transverse elements 26which make up the base 20 are made of a material, for example,reinforced concrete, which is heavy enough to restrain the structure onthe bed and sufficiently resistant to the erosion that is caused by thewave motion over time.

According to another preferred embodiment of the present invention, thewave-motion reducing means directly comprise restraining means forenabling them to be engaged on the sea bed. The wave-motion reducingstructure thus does not include a base that is laid on the coastal bedsince the wave-motion reducing means are restrained on the bed directly.By way of non-limiting example, the panel 30 comprises a lower portion31 which can be inserted directly into a sandy bed so as in any case toachieve a firm restraint.

Naturally, the composition and configuration of the elements forming thebase of the structure may vary widely with respect to those describedabove, without thereby departing from the scope of the presentinvention. By way of non-limiting example, the base may comprise threeor more longitudinal elements 20 or, alternatively, may not includetransverse elements 26, or may even comprise a single substantiallyparallelepipedal base block in which the seats 21 housing the inclinedpanels 30 are formed, as described and illustrated above.

One of the advantages of the present invention is that it is possible toconstruct different configurations of the restraining means which in anycase achieve greater stability on the coastal bed on which they operatewithout a simultaneous excessive increase in their weight, so thattransportation and laying are easy and do not require the use of specialtools for the purpose.

FIG. 4 shows a wave-motion reducing system according to the invention.It is composed of a plurality of wave-motion reducing structures 10 asdescribed above, preferably four structures with their bases 20 arrangedin a row lengthwise and in a manner such that the respective panels 30adopt a substantially parallel configuration and oppose the wave motionof the sea current. The structures 10 are in turn placed side by side sothat several panels are arranged side by side to form a continuouspanel, or the structures 10 are constituted by bases housing panelswhich, preferably but in non-limiting manner, reach a length of between15 and 25 metres, in particular 20 metres. Tests have found that thebases preferably have a length of 6 metres in the direction of the wavemotion and the panels have a height of 1.5 metres and are inclined at45°. The system is preferably laid on a bed having a depth of about 3metres.

In regions in which the structures configured as explained above mightgive rise to erosion, the system advantageously comprises anti-erosionfilter means, for example, but in non-limiting manner, made ofgeo-textile material weighted with a metal mesh which is preferablyplastics-coated. Naturally, the filter means may be made of differentknown elements, for example, of ballasted mats which may help torestrain the structure on the sea bed.

A particularly advantageous configuration of the wave-motion reducingsystem is shown in FIG. 5 in which ballasted filter mats 40 alternate,in the direction transverse the wave motion, with wave-motion reducingstructures configured as described above. The system is preferablyconfigured with the filter mats forming, between the structures,corridors having a width of about 6 metres and a length, in thedirection of the wave motion, which is comparable to the overall lengthof the structures. Moreover, the wave-motion reducing system preferablyextends for a distance of about 100 metres transversely relative to thewave motion and also has, at the edges of the wave-motion reducingstructures 10, further filter mats 41 of a width comparable to that ofthe structures 10. Tests have shown that this particular configurationof the wave-motion reducing system considerably reduces erosion andeliminates any currents that may also pose a risk to bathers.

Naturally many variants of the wave-motion reducing structure and systemof the invention may be provided without thereby departing from thescope of the present invention.

1.-17. (canceled)
 18. A wave-motion reducing system comprising aplurality of structures having a base disposed on a coastal bed,engagement elements obtained on the base, and at least a panel engagedto the base through the engagement elements, wherein the structures arealigned side by side along a row extending toward the coast, the panelsadopting a configuration substantially parallel to one another andopposing the wave motion of a sea current.
 19. A wave-motion systemaccording to claim 18, wherein the system further comprises a pluralityof rows of structures where the panels adopt a configurationsubstantially parallel to one another and opposing the wave motion of asea current, the rows being arranged side by side in a directiontransverse to the wave motion.
 20. A wave-motion system according toclaim 19, further comprising filter means.
 21. A wave-motion systemaccording to claim 20, wherein the filter means alternate with the rowof wave-motion reducing structures in a direction transverse to the wavemotion.
 22. A wave-motion system according to claim 21, wherein thefilter means comprise geo-textile material ballasted with a metal meshwhich is plastics-coated.
 23. A wave-motion system according to claim22, further comprising filter means arranged at the edges of the rows ofwave-motion reducing structures.
 24. A wave-motion system according toclaim 23, wherein the filter means have a width of about 6 meters whenthey alternate with the structures and a width comparable to that of thestructures when they are arranged at the edges of the structures, thesystem extending for about 100 meters in a direction transverse to thewave motion.
 25. A wave-motion system according to claim 18, wherein theengagement elements comprise two parallel projecting walls which areinclined to the vertical, defining a seat particularly suitable forhousing the wave-motion reducing means in use.
 26. A wave-motion systemaccording to claim 18, wherein the base comprises a plurality oflongitudinal blocks arranged parallel to one another and interconnectedby transverse elements.
 27. A wave-motion system according to claim 18,wherein the panel comprises an upper portion and a lower portion, thelower portion being restrained on the coastal bed.
 28. A wave-motionsystem according to claim 27, wherein the panel is restrained on thecoastal bed so as to be arranged at an inclination of between 30° and90° to the horizontal.
 29. A wave-motion system according to claim 28,wherein the panel is restrained on the coastal bed so as to be arrangedat an inclination of 45° to the horizontal.
 30. A wave-motion systemaccording to claim 28, wherein the panel is restrained on the coastalbed so as to be arranged at an inclination of 60° to the horizontal. 31.A wave-motion system according to claim 18, wherein the base isconstituted by a single block of material.
 32. A method of constructinga wave-motion reducing system, comprising the steps of: providing aplurality of wave-motion reducing means, each wave-motion reducing meanscomprising a base and a panel, arranging the wave-motion reducing meansso as to form a row along a preferred direction toward the coast, andarranging the wave-motion reducing means so that the panels adopt aconfiguration substantially parallel to one another and inclined againstthe direction of the sea current and opposing the wave motion of a seacurrent.